Defect and maintenance detection for image capture device

ABSTRACT

Defect and maintenance detection for an image capture device (ICD) capable of distinguishing between a defect in the ICD and one on the imaged object. The defect detection system includes, inter alia: a value combiner that combines a brightest image video value for each sensing element of the ICD experiencing the imaged object with a corresponding stored device video value to create a combined value for each image video value; and a defect determinator determines the presence of a defect(s) by comparing the combined values to a defect threshold. The maintenance detection system includes a determinator that determines when maintenance is required based on whether a single image is considered defective or whether a number of consecutive defective images have been created. Device video values are updated sluggishly according to corresponding image video values.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a continuation of U.S. patent application Ser. No.09/862,050, filed May 5, 2001 now U.S. Pat. No. 7,031,026.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates generally to a method and apparatus fordetecting when a defect is present in an image capture device such as ascanner and when maintenance is required. More particularly, the presentinvention relates to a method and apparatus for detecting a defect in animage capture device that can distinguish between an defect in the imagecapture device and one on the imaged object; and a method, apparatus andcomputer program product for detecting when maintenance is required.

2. Related Art

Digital imaging of documents, photographs and other objects providesnumerous advantages including the ability to easily process, analyze andcommunicate images. One common method of creating a digital image isscanning using an image capture device such as a scanner. An imagecapture device typically includes a bar, or line, of illumination and aplurality of sensing elements such as a charge-coupled device (CCD). Thesensing elements create the digitized image of the object. There are avariety of different type image capture devices such as a desktop flatbed scanner, a desktop document feed scanner or a higher speed,industrial variation of either scanner. An object to be imaged istypically either moved over the sensing elements (feed-type) or thesensing elements are moved over the object (flat-bed type).

During scanning, defects such as build up of ink, smudges, dust,moisture, etc., on component(s) of the image capture device can causestreaky or defective images. Such defects may occur, for example, in theillumination path between the sensing elements and the object beingimaged (e.g., between CCDs and the glass platen) and/or the imaging paththrough which the sensing elements or object passes (e.g., on the glassplaten) and/or on the sensing elements themselves.

In related art devices, imaging non-uniformities are compensated forusing the image capture device's calibration process. Typically, imagecapture device calibration steps alter the video gain and offset so thata uniform emmissivity imaged object produces uniform video. Followingcalibration, any localized defects caused by the image capture devicecan result in a locally reduced video value leading to streaky images.Hence, detection of the presence of defects in an image capture deviceis necessary.

One challenge for detecting when maintenance is required to correct andefect is to be able to distinguish between a streak resulting fromhardware, namely the image capture device components, and defectsresulting from the object being scanned. Related art devicesinadequately address this challenge and, as a result, may give falseindications of when maintenance is required to correct a defect in theimage capture device.

Another challenge for detecting when maintenance is required is notmaking premature false indications for problems that may self-correct.For instance, a piece of dust may cause a defect, but the piece of dustmay be removed through normal operation of the image capture device,e.g., removal by a subsequent imaged object, aerodynamic activity in anindustrial scanner, etc. In certain circumstances, a limited number ofdefective images created by the piece of dust may be acceptable. In thiscase, an indication that maintenance is required before the imaging ofthe acceptable number of objects is unnecessary. Related art devicesinadequately address this self-correcting defect challenge and may givepremature false indications.

In view of the foregoing, there is a need in the art for defect andmaintenance detection in an image capture device that can distinguishbetween a defect in the image capture device and one on the imagedobject.

SUMMARY OF THE INVENTION

A first aspect of the invention is directed to a maintenance detectionsystem for use with an image capture device having a plurality ofsensing elements for creating an image of an object, the systemcomprising: a device video profiler that accesses a stored device videovalue for each sensing element; an image video profiler that acquires animage video value for each sensing element that experiences the object,each image video value representing a brightest video value experiencedby the respective sensing element during imaging of the object; a valuecombiner that combines each image video value with a correspondingdevice video value to create a combined value for each image videovalue; a defect determinator that determines the presence of a defect inthe image capture device based on a combined value exceeding a defectthreshold; and a maintenance determinator that determines whenmaintenance is required based on the defect determinator outcome.

A second aspect of the invention is directed to an imaging systemcomprising: an image capture device for imaging an object; an imagecapture processor; and a maintenance detection system as discussedabove.

A third aspect of the invention provides a defect detection system foruse with an image capture device having a plurality of sensing elementsfor imaging an object, the system comprising: a device video profilerthat accesses a stored device video value for each sensing element; animage video profiler that acquires an image video value for each sensingelement that experiences the object, each image video value representinga brightest video value experienced by the respective sensing elementduring imaging of the object; a value combiner that combines each imagevideo value with a corresponding device video value to create a combinedvalue for each image video value; and a defect determinator thatdetermines when a defect is present on the image capture device based ona combined value exceeding a defect threshold.

A fourth aspect of the invention is directed to a method for detectingwhen maintenance is required in an image capture device having aplurality of sensing elements for imaging an object, the methodcomprising the steps of: a) accessing a device video value for eachsensing element; b) imaging an object with the image capture device; c)acquiring an image video value for each sensing element that experiencesthe object, each image video value representing a brightest video valueexperienced by the respective sensing element during imaging of theobject; d) combining each image video value with a corresponding devicevideo value to create a combined value for each image video value; e)determining a defect is present in the image capture device for eachcombined value that exceeds a defect threshold; f) determining whenmaintenance is required based on the presence of at least one defect;and g) indicating when maintenance is required for the image capturedevice.

A fifth aspect of the invention provides a system for determining whenmaintenance is required in an image capture device, the systemcomprising: means for accessing a plurality of device video values forthe image capture device; means for acquiring a plurality of image videovalues as an object is imaged by the image capture device; means forcombining each image video value with a corresponding device video valueto create a combined value; means for detecting a defect by comparingeach combined value to a defect threshold to determine the presence of adefect; and means for determining when maintenance is required based onthe outcome of the means for detecting a defect.

A sixth aspect of the invention provides a defect detection system foruse with an image capture device having a plurality of sensing elementsfor imaging an object, the system comprising: means for accessing aplurality of device video values for the image capture device; means foracquiring a plurality of image video values as an object is imaged bythe image capture device; means for combining each image video valuewith a corresponding device video value to create a combined value; andmeans for comparing each combined value to a defect threshold todetermine the presence of a defect.

A final aspect of the invention provides a computer program productcomprising a computer useable medium having computer readable programcode embodied therein for determining when maintenance is required in animage capture device having a plurality of sensing elements for imaginga plurality of objects, the computer program product comprising: programcode configured to access a device video value for each sensing element;program code configured to acquire an image video value for each sensingelement that experiences an object as the object is imaged, wherein eachimage video value represents a brightest video value experienced by therespective sensing element during imaging of the object; program codeconfigured to compare each combined value of the image to a defectthreshold to determine the presence of a defect; program code configuredto determine whether the image is defective as defined by a defect countof defects in the image exceeding a defect count threshold; and programcode configured to determine maintenance is required when a consecutivedefective image count exceeds an image count threshold.

The foregoing and other features and advantages of the invention will beapparent from the following more particular description of preferredembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of this invention will be described in detail,with reference to the following figures, wherein like designationsdenote like elements, and wherein:

FIG. 1 shows a block diagram of an imaging system including defect andmaintenance detection systems in accordance with the invention; and

FIGS. 2A-B show a flow diagram of a method in accordance with theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a block diagram of an imaging system 2 including an imagecapture device 4 for imaging an object 6 and a maintenance detectionsystem 8 including a defect detection system 9 in accordance with thepresent invention. Image capture device 4 may also be a separatecomponent from imaging system 2.

System 2 preferably includes a memory 12, a central processing unit(CPU) 14, input/output devices (I/O) 16 and a bus 18. A database 21 mayalso be provided for storage of data relative to processing tasks.Memory 12 preferably includes a program product 20 that, when executedby CPU 14, comprises various functional capabilities described infurther detail below. Memory 12 (and database 21) may comprise any knowntype of data storage system and/or transmission media, includingmagnetic media, optical media, random access memory (RAM), read onlymemory (ROM), a data object, etc. Moreover, memory 12 (and database 21)may reside at a single physical location comprising one or more types ofdata storage, or be distributed across a plurality of physical systems.CPU 14 may likewise comprise a single processing unit, or a plurality ofprocessing units distributed across one or more locations. I/O 16 maycomprise any known type of input/output device including a networksystem, modem, keyboard, mouse, scanner, voice recognition system, CRT,printer, disc drives, etc. Additional components, such as cache memory,communication systems, system software, etc., may also be incorporatedinto system 2.

Imaging system 2 may be implemented in a variety of forms. For example,imaging system 2 may be implemented as part of an IBM 3897 Model 4 ImageCapture System. Alternatively, imaging system 2 may be part of a highspeed, high volume document processing system such as found ininstitutional banks. In this case, system 2, as recognized in the field,may include one or more networked computers, i.e., servers. A servercomputer typically comprises an advanced mid-range multiprocessor-basedserver, such as the RS6000 from IBM, utilizing standard operating systemsoftware, which is designed to drive the operation of the particularhardware and which is compatible with other system components, and I/Ocontrollers.

Alternatively, system 2 may be implemented as part of a workstation suchas a bank teller workstation. A workstation of this form may comprise,for example, an INTEL PENTIUM III microprocessor, or like processor,such as found in an IBM APTIVA computer.

Memory 12 of system 2 preferably includes a program product 20 that,when executed by CPU 14, provides various functional capabilities forsystem 2. As shown in FIG. 1, program product 20 may include maintenancedetection system 8, a comparator 30 and other system component(s) 22.Other system component(s) 22 may include any well known image processingsystem components, e.g., an image capture processor. Maintenancedetection system 8 includes defect detection system 10, a maintenancedeterminator 29 and a counter 32. Defect detection system 10 includes adevice video profiler 24, an image video profiler 26, a value combiner28, and a defect determinator 34. While a single comparator 30 has beendisclosed, which is accessed by maintenance detection system 8 and/ordefect detection system 10, as necessary, each system 8, 10 may includetheir own comparator.

In the following discussion, it will be understood that the method stepsdiscussed preferably are performed by a processor, such as CPU 14 ofsystem 2, executing instructions of program product 20 stored in memory.It is understood that the various devices, modules, mechanisms andsystems described herein may be realized in hardware, software, or acombination of hardware and software, and may be compartmentalized otherthan as shown. They may be implemented by any type of computer system orother apparatus adapted for carrying out the methods described herein. Atypical combination of hardware and software could be a general-purposecomputer system with a computer program that, when loaded and executed,controls the computer system such that it carries out the methodsdescribed herein. Alternatively, a specific use computer, containingspecialized hardware for carrying out one or more of the functionaltasks of the invention could be utilized. The present invention can alsobe embedded in a computer program product, which comprises all thefeatures enabling the implementation of the methods and functionsdescribed herein, and which—when loaded in a computer system—is able tocarry out these methods and functions. Computer program, softwareprogram, program, program product, or software, in the present contextmean any expression, in any language, code or notation, of a set ofinstructions intended to cause a system having an information processingcapability to perform a particular function either directly or after thefollowing: (a) conversion to another language, code or notation; and/or(b) reproduction in a different material form.

For purposes of explanation, object 6 may be described as a document,e.g., a check or a letter. It should be recognized, however, that theteachings of the present invention may be applied to any image capturedevice regardless of the object being imaged. Other object examplesinclude, but are not limited to, photographs and lithographs.

Returning to FIG. 1, an object to be imaged 6 is fed through or placedwithin an image capture device 4. Image capture device 4 may be any typeof now known or later developed scanner. For instance, image capturedevice 4 may be a desktop flat bed scanner, a desktop document feedscanner or a higher speed, industrial variation of either scanner. Asknown in the art, image capture device 4 (hereinafter “ICD 4”) includesa bar, or line, of illumination and a plurality of sensing elements (notshown) such as charge-coupled devices (CCD). An object 6 to be imaged iseither moved over sensing elements (feed-type) or sensing elements aremoved over the object (flat-bed type). As an object is imaged, eachsensing element of ICD 4 adjacent object 6 obtains a video value(representative of pel location). Furthermore, each sensing element ofICD 4 that experiences (i.e., sees) the object 6 will in most cases, atsome point during the object's imaging, see a brighter region of theobject. In terms of documents, this region is commonly white.

Referring to FIGS. 2A-B, operation of maintenance detection system 8 anddefect detection system 10 will be explained. Steps S1-S5 and S11represent operation of defect detection system 10, and steps S1-S11represent operation of maintenance detection system 8.

Defect Detection:

At the START of the system logic, system 8 parameter(s) may beinitialized. For instance, a consecutive defective image count, whichwill be described in greater detail below, is initialized by setting itto zero. In addition, if used, a defect count may be initialized bysetting it to zero.

In a first step S1, a device video value is accessed by device videoprofiler 24 (FIG. 1) for each sensing element of ICD 4. Each devicevideo value is representative of a brightest video value sensed by acorresponding sensing element of ICD 4 over a period of time. Devicevideo values are stored, for example, in database 21. If an ICD 4 has,for example, 1024 sensing elements, 1024 device video values areprovided. Actual device video values will vary according to the type ofvideo system being used. For instance, for an 8 bit video system, videovalues range from 0 (darkest) to 255 (brightest). Other ranges of videovalues may be implemented for other video systems, e.g., a 10, 12 or 14bit system.

Since each device video value is representative of a brightest videovalue sensed over a period of time, as defects in ICD 4 arise, such asbuild up of ink, smudges, dust, moisture, imperfections, etc., devicevideo values will become darker. For purposes of this disclosure, whiledefects will be described as “in” ICD 4, it should be recognized thatthe term covers all matters of defects in, on or between any workingpart of ICD 4. Each device video value, as will be described below, isupdated after each object 6 is imaged. Hence, each device video valuemay change over time, i.e., be indicative of brighter or darkersituations. For a hypothetical 8 bit video ICD 4 that is completelyclean of any defects, each device video value will be 255 orthereabouts. In reality, device video values will not be uniform, andmay exhibit high frequency variations. For instance, a small sample foran 8-bit system may include values: 238, 240, 242, 215, 227.

Next, at step S2, an object 6 is imaged with ICD 4 in a known fashion.

At step S3, an image video value for each sensing element (i.e., pellocation) that experiences the object is acquired by image videoprofiler 26 (FIG. 1). Each image video value represents a brightestvideo value experienced/sensed by a respective sensing element of ICD 4that experiences/senses object 6 as it is imaged. Hence, each imagevideo value represents a brightest video value based on object 6 and ICD4. For example, for a document that covers 800 sensing elements, therewill be 800 image video values. If a sensing element first senses abrightness of 220 and afterwards a brightness of 225, the image videovalue will be the 225 value.

Next, at step S4, value combiner 28 (FIG. 1) combines each image videovalue with a corresponding device video value to create a combined valuefor each image video value. Since an object 6 may not be large enough toinclude every sensing element of ICD 4, only those image video valuesacquired will be combined with a corresponding device video value. Thatis, system 8 only calculates a combined value for a region of sensingelements of ICD 4 that experience object 6.

In terms of the actual combination of values, value combiner 28 mayoperate in a number ways. In one embodiment, the actual image videovalue and the actual corresponding device video value may be multipliedto arrive at a corresponding combined value. In another embodiment, theimage video value and corresponding device video value may, prior tocombining, each be subtracted from a brightest available video value(e.g., 255 in an 8 bit system) to create a darkness value for each. Forinstance, for a device video value of 230, a device darkness value wouldbe 25 (255−230). Each darkness value may then be combined, e.g.,multiplied, to create the combined value. For purposes of thisdisclosure, however, the terms “image video value” and “device videovalue” should be considered to include either the actual video valuesthat are directly indicative of brightness or their equivalent darknessvalues. Other mathematical operations that meaningfully combine the twovideo values may also be implemented. For instance, the video values maybe added together or weighted in some fashion.

If a defect is building in an area of ICD 4 (e.g., because of dustaccumulation), those sensing elements corresponding to that area havedarker device video values. If device video values were put into agraph, the values would indicate a valley, e.g., “ . . . 238, 234, 230,215, 225, 234, 237 . . . .” A darker device video value alone is notaccurately indicative of a defect in ICD 4 since an object 6 havingdarker regions may cause a darker device video value. When a darkerdevice video value and a darker image video value are in-phase (i.e., inthe same pel location), however, it is a good indication that a defectis present in ICD 4 at the video value (pel) location. The combinedvalue indicates when these values are in-phase by combiningcorresponding device and image video values. An abnormality in thecombined value (i.e., peak or depression depending on type of combinedvalue used), especially one that repeats over the imaging of a number ofobjects 6, is a strong indication that a defect exists on ICD 4 at thevideo value (pel) location. Hence, the combined value amplifies thelocation of a defect in ICD 4 (and distinguishes the dark situation fromone created by the object alone) by indicating where a device videovalue and an image video value are in-phase.

In step S5, defect determinator 34 determines the presence of one ormore defects in the ICD 4 based on one or more combined values exceedinga defect threshold. More particularly, defect determinator 34 determinesthe presence of a defect(s) in ICD 4 by comparing each combined value toa defect threshold using comparator 30. As used herein the term “exceed”or “exceeding” should be interpreted to include a subject count or valuegoing beyond (in a positive or negative sense depending oncircumstances) or meeting a respective threshold. The “defect threshold”is a number that when compared to a combined value indicates anunacceptable dark situation, i.e., a defect, at the particular videovalue location. Hence, the defect threshold defines when a darksituation is a defect. The defect threshold may be user defined. Adefect threshold may be, for example, 52,900 (device video value 230times image video value 230) where actual video values are used. Hence,a low combined value may exceed the defect threshold. In contrast, wheredarkness values are used to create the combined value, a defectthreshold may be 144 (device darkness value 12 times object darknessvalue 12). In this case; a high combined value may exceed a defectthreshold.

If defect detection system 10 alone is used, logic proceeds to step S11,as described below. If maintenance detection is desired, logic proceedsas follows.

Maintenance Required Detection:

Referring to FIG. 2B, in steps S6-S11, maintenance determinator 29determines when maintenance is required based on the defect determinator34 outcome. More particularly, the determination can be based on whetheran image is defective as defined by a defect count exceeding a defectcount threshold. Alternatively, the maintenance determinator maydetermine when maintenance is required based on whether a consecutivedefective image count exceeds an image count threshold.

A) Determining Whether an Object Image is Defective:

In step S6, a determination as to whether an object image is defectiveis made. The determination includes determining whether enough defectsare present to warrant the image being considered defective.

In one embodiment, an object image is considered a defective image onlywhen it contains a number of defects (>1) (which is maintained in adefect count) that exceeds a defect count threshold. Hence, the defectcount threshold defines when an object image is a defective image. Adefect count threshold may be set by a user to any number according to,for example, their tolerance for defects and/or the particular ICD 4being used. The defect count is maintained and incremented by one bycounter 32 (FIG. 1) for each defect. That is, for every particularlocation (i.e., an image video value and a corresponding device videovalue location) that creates a combined value exceeding the defectthreshold, counter 32 increments the defect count for that image by one.Hence, for an image having X defects (where X is an integer), the defectcount is X. Whether the defect count exceeds the defect count thresholdmay be determined, for example, by comparator 30 comparing the defectcount for each image to the defect count threshold.

In another embodiment, only a single defect in an image may indicate adefective image. In this case, maintenance detection system 8 may simplymake a determination that an image is defective when any combined valueexceeds a defect threshold. In other words, maintenance detection system8 may set the defect count threshold to one. In this case, the defectcount simply fluctuates between zero and one.

If maintenance detection system 8 requires only a single defective imageto indicate maintenance is required, steps S7-S9 are skipped, and a‘maintenance required’ indication is given, at step S10, via an outputmechanism of I/O 16, e.g., a display, a monitor, speaker, etc., ofimaging system 2. Logic would then proceed to step S11, which isdiscussed below.

B) Determining Whether a Consecutive Defective Image Count Exceeds anImage Count Threshold:

Maintenance detection system 8 may also preferably determine whenmaintenance is required based on whether a number of defective imageshave been created by ICD 4, i.e., a consecutive defective image countexceeds an image count threshold. This setup requires a plurality ofimages to be created by ICD 4. The “consecutive defective image count,”as the name implies, tracks how many consecutive defective images havebeen created.

Turning to step S7, if an image is determined not to be defective atstep S6, a consecutive defective image count is reset to zero. Theprocess then continues with step S11, which will be described below. Incontrast, if the image is determined to be a defective image (step S6),at step S8, counter 32 (FIG. 1) increments the consecutive defectiveimage count by one.

Next, at step S9, a determination is made by comparator 30 as to whetherthe consecutive defective image count exceeds an image count threshold.The “image count threshold” is a number that when exceeded indicates anICD 4 has experienced enough consecutive defective images to indicatemaintenance is required. If the consecutive defective image countexceeds the image count threshold, at step S10, a ‘maintenance required’indication may be made via an output mechanism of I/O 16, e.g., adisplay, a monitor, speaker, etc., of imaging system 2. The image countthreshold may be selected by the user, and may vary, for instance,according to the type of ICD 4 and the defect tolerance a user iswilling to accept.

A user may select an image count threshold of one, which nulls the useof the consecutive defective image count and image count threshold.However, it is more preferable that the image count threshold exceedsone. The reason for this is that most objects 6 have some dark areasstretching the length of the object that could cause a false indication.However, using an image count threshold greater than one prevents arandom object 6 having a darkened region (e.g., a document with asmudge) from causing a false ‘maintenance required’ indication.Assigning a higher value for the image count threshold also requiressystem 8 to experience a number of defective image(s) with a defect inthe same location to have a false indication. Because objects areunlikely to have dark bands in the same location, a false indication ishighly unlikely.

In addition, setting a higher image count threshold prevents prematurefalse indications for problems that may self-correct. For instance, apiece of dust may cause a defect for an acceptable number of imagedobjects. The piece of dust may then be removed through normal operationof the image capture device, e.g., removal by a subsequent imagedobject, aerodynamic activity in an industrial scanner, etc. A user mayset the image count threshold to five (5) and, hence, accept fourdefective images before an indication is made. Exemplary image countthresholds may be: 50-100 for an industrial scanner, or 5-10 passes fora desktop scanner.

Turning to step S11, each device video value that was used to create acombined value (referred to as a “used device video value”) is updatedby device video value profiler 24. In addition, the defect count isreset to zero.

As discussed above, step S11, could follow step S6, if only a singledefective image is required to indicate maintenance is required, i.e.,steps S7-S9 are not used. When a number of consecutive defective imagesare required (i.e., steps S7-S9 are used), step S11 is implemented when,at step S9, the consecutive defective image count does not exceed theimage count threshold. Logic then returns to step S1 for another objectimaging, or ends.

The updating of step S11 is such that the updated device video valuereflects a measure of a corresponding image video value. Moreparticularly, a device video value used to create a combined value isdiminished (i.e., given a darker value) when the corresponding imagevideo value is darker than the used device video value, and enlargedwhen the corresponding image video value is brighter than the useddevice video value. However, the step of updating each device videovalue occurs in a “sluggish” or “low pass filter” manner. That is, adevice video value is not altered quickly or in large amounts.

However, each updated device video value is adjusted towards a brightervalue more quickly than towards a darker value. This technique providesprotection from a random object 6 having a dark defect, or a string ofobjects having dark defects, adversely effecting the device video valuesand hence the determination of defects. This further prevents falseindications. This technique also allows systems 8, 10 to be able todistinguish between a defect resulting from hardware, namely the ICDcomponents, and defects resulting from the object 6 being imaged becauseonly those defects that repeat in a location effect the device videovalues. That is, defects that do not move from location to location aremore likely on the hardware.

In order to accomplish this updating operation, in one embodiment, adifference between each image video value and a corresponding useddevice video value is determined. Then, the used device video value maybe updated at a greater portion of the difference when the correspondingimage video value is brighter than the used device video value versuswhen the corresponding image video value is darker than the used devicevideo value.

In another embodiment, a used device video value may be updated bycombining: a) a first percentage of the used device video value, and b)a second percentage of a corresponding image video value. In this case,the second percentage is greater when the corresponding image videovalue is brighter than the used device video value versus when thecorresponding image video value is darker than the used device videovalue. For instance, where the used device video value is 235 and theimage video value is 215 (darker), the first percentage may be 90% andthe second percentage 10%. In contrast, where the used device videovalue is 235 and the image video value is 245 (brighter), the firstpercentage may be 50% and the second percentage 50%.

Although a couple of techniques have been described to weight thedifferent video values, one with skill in the art will recognize thatother approaches are possible. Accordingly, the invention should not belimited to the techniques described above but rather should include anynow known or later developed weighting techniques. Furthermore, whileprocessing has been described in which device video values have beenupdated after each object is imaged, it should be recognized that thesevalues may be updated at other periods such as after passage of a timeperiod.

It should also be recognized that while the device video profiler 24 hasbeen described as the component that accesses and updates device videovalues, the profiler may be further compartmentalized. Furthermore,other system components may be arranged in other functionalcombinations. For instance, defect detection system 10 may be utilizedseparate from maintenance detection system 8.

The above described systems and methods provide a mechanism fordetecting when maintenance is required for an ICD. Further, they providea mechanism that is capable of distinguishing between defects of an ICDand an object.

While this invention has been described in conjunction with the specificembodiments outlined above, it is evident that many alternatives,modifications and variations will be apparent to those skilled in theart. Accordingly, the preferred embodiments of the invention as setforth above are intended to be illustrative, not limiting. Variouschanges may be made without departing from the spirit and scope of theinvention as defined in the following claims.

1. A maintenance detection system for use with an image capture devicehaving a plurality of sensing elements for creating an image of anobject, the system comprising: a device video profiler that accesses astored device video value for each sensing element; an image videoprofiler that acquires an image video value for each sensing elementthat experiences the object, each image video value representing abrightest video value experienced by the respective sensing elementduring imaging of the object; a value combiner that combines each imagevideo value with a corresponding device video value to create a combinedvalue for each image video value; a defect determinator that determinesthe presence of a defect in the image capture device based on a combinedvalue exceeding a defect threshold; and a maintenance determinator thatdetermines when maintenance is required based on the defect determinatoroutcome.
 2. The system of claim 1, wherein the maintenance determinatordetermines when maintenance is required based on whether the image isdefective as defined by a defect count exceeding a defect countthreshold.
 3. The system of claim 2, wherein the defect count thresholdexceeds one.
 4. The system of claim 1, wherein the image capture devicecreates a plurality of images and the maintenance determinator:determines whether each image is defective as defined by a defect countexceeding a defect count threshold; and determines maintenance isrequired when a consecutive defective image count exceeds an image countthreshold.
 5. The system of claim 4, wherein the consecutive defectiveimage threshold exceeds one.
 6. The system of claim 4, wherein thedefect count threshold exceeds one.
 7. An imaging system comprising: animage capture device for imaging an object; an image capture processor;and a maintenance detection system as recited in claim
 1. 8. A defectdetection system for use with an image capture device having a pluralityof sensing elements for imaging an object, the system comprising: adevice video profiler that accesses a stored device video value for eachsensing element; an image video profiler that acquires an image videovalue for each sensing element that experiences the object, each imagevideo value representing a brightest video value experienced by therespective sensing element during imaging of the object; a valuecombiner that combines each image video value with a correspondingdevice video value to create a combined value for each image videovalue; and a defect determinator that determines when a defect ispresent on the image capture device based on a combined value exceedinga defect threshold.
 9. The system of claim 8, wherein the defectthreshold is defined by a user.
 10. A system for determining whenmaintenance is required in an image capture device, the systemcomprising: means for accessing a plurality of device video values forthe image capture device; means for acquiring a plurality of image videovalues as an object is imaged by the image capture device; means forcombining each image video value with a corresponding device video valueto create a combined value; means for detecting a defect by comparingeach combined value to a defect threshold to determine the presence of adefect; and means for determining when maintenance is required based onthe outcome of the means for detecting a defect.
 11. The system of claim10, wherein the image capture device creates a plurality of images andthe means for determining: determines whether an image is defective asdefined by a defect count for that image exceeding a defect countthreshold; and determines maintenance is required when a consecutivedefective image count exceeds an image count threshold.
 12. A defectdetection system for use with an image capture device having a pluralityof sensing elements for imaging an object, the system comprising: meansfor accessing a plurality of device video values for the image capturedevice; means for acquiring a plurality of image video values as anobject is imaged by the image capture device; means for combining eachimage video value with a corresponding device video value to create acombined value; and means for comparing each combined value to a defectthreshold to determine the presence of a defect.
 13. A computer programproduct comprising a computer useable medium having computer readableprogram code embodied therein for determining when maintenance isrequired in an image capture device having a plurality of sensingelements for imaging a plurality of objects, the computer programproduct comprising: program code configured to access a device videovalue for each sensing element; program code configured to acquire animage video value for each sensing element that experiences an object asthe object is imaged, wherein each image video value represents abrightest video value experienced by the respective sensing elementduring imaging of the object; program code configured to compare eachcombined value of the image to a defect threshold to determine thepresence of a defect; program code configured to determine whether theimage is defective as defined by a defect count of defects in the imageexceeding a defect count threshold; and program code configured todetermine maintenance is required when a consecutive defective imagecount exceeds an image count threshold.